Iris Unguicularis

Winter with the Iris Unguicularis

If you are new to the iris unguicularis you will find it to be one of those plants you can toss on the back of the garden and forget. Come late fall-November or so, you will not believe the lovely little flowers that dress up the otherwise sleeping area of the yard. What will make the experience even nicer is when you bring a bloom or two in and have the fragrance permeate the room with a delightful mixture of vanilla/honey/lemon. The third wonderful surprise is watching the plant bloom throughout the winter-snow and all. 

Known as the gem of its genus, because of its bloom time the Iris unguicularis starts blooming sometime in late October and continues through March-perhaps even April according to your growing zone. If your winters are not severe, even when the temperature dips into the teens or single digits-and though the plants will all freeze and turn to mush, when the weather warms the following week this hardy plants will send up new shoots.  If the weather holds before long you will again be enjoying its blooms. 

The leaves of the Iris unguicularis are about ½ inch wide and grow to about 15" long ranging in color from a bright green to almost grey blue. The flowers are usually shades of lavender but can vary from all white to a very deep purple. These irises are not very showy from a distance but so lovely up closer when everything else is lifeless.

Irises themselves are a diverse collection of bulbs and rhizomes, with over 200 species to choose from. Of the numerous varieties there are three main categories: bearded, beardless and crested, with bearded iris are the most popular and well known. The beardless iris unguicularis is Mediterranean in origin-found through out Greece and northern Africa but are widely planted in gardens all across the world.


Though the natural habitat of the iris unguicularis is a lightly shaded rocky setting these plants seem to thrive in full sun, on neglect or in an unlikely soil medium. Young plants that have been grown from division do require watering during their first year. If dividing these irises the fall is the better time-though spring is okay. They will establish better through the winter though that first year. If you are planting in pot there is no better time. They do well no matter when divided.

Feeding or any sort of soil improvement does not help these plants-and actually seems to be counter-productive. There main pest problem come in the form of slugs and snails which tend to hide in the dense clumps of leaves and flowers-feasting on the flowers in the winter. The iris borer (larval form of a moth) can be another serious pest in some parts of the country-northern area. These are characteristic of small sawdust-type piles near the bulb or rhizome; except where winter temperatures remain above 10F. Here there is little problem. Clean out debris from around the base of plants in the winter where larva is staying warm to help any bore problems and a bait of slug pellets (saucer of beer next to the plant early in the winter) will help to draw slugs and snails away from plants.

Iris unguicularis tends to flower in splendidly on its own but does have some excellent low growing compatibles such as late winter, early spring crocuses, daffodils, etc.  In close quarters this iris has a tendency to sprawl so prepare for it.

A light application of fertilizer in the fall and spring (after blooming is complete) is helpful but with this plant not at all necessary. The foliage clumpings have a tendency to hang onto their dead leaves, and need to be tidied up to keep the plants from looking unkempt.